1. Field of the Invention
This invention generally relates to a bicycle hub with a detachable freewheel. More specifically, the present invention relates to a bicycle hub with a spacer provided on a two-part axle to allow separation of a sprocket support member from the hub without removing the freewheel from the bicycle frame.
2. Background Information
Bicycling is becoming an increasingly popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the components of the bicycle. One particular component of the bicycle, which has been extensively redesigned over the past years, is the rear bicycle hub.
Specifically, most bicycles have several speeds. Accordingly, the rear bicycle hub usually includes a freewheel. The freewheel includes at least one chain engaging sprocket. One popular form of drive train and freewheel for a bicycle includes a plurality of sprockets that are mounted on the hub of the rear bicycle wheel. During pedaling, the bicycle chain engages one of the rear sprockets to rotate the rear wheel. When bicycle rider stops pedaling, the rear wheel should be able to continue to rotate while the sprockets remain stationary. Accordingly, the rear hub is usually provided with a freewheel that has a one-way clutch.
Freewheels are used to transmit a driving force to the rear bicycle wheel in one rotation direction only. These freewheels are usually mounted on the rear hub of a bicycle. Freewheels typically allow the bicycle to advance freely without any rotation of the pedals. Freewheels usually include boss type freewheels which are mounted on the boss of the rear hub by being screwed onto the rear hub, and free hub type freewheels which are fastened to the rear hub as integral parts of the rear hub. Both types of freewheels are equipped with an outer tubular part, an inner tubular part which is installed radially inwardly of the outer tubular part so that the inner tubular part is free to rotate relative to the outer cylinder part. A one-way clutch is installed between the outer tubular part and inner tubular part for transmitting the driving force from the outer tubular part to the inner tubular part in one rotational direction only. The outer tubular part usually has a plurality of gears mounted thereon, while the inner tubular part is usually mounted on the rear hub of the bicycle.
Splines are formed between the sprocket wheels and boss to prohibit relative rotation therebetween positively. Since this unit is used for the rear wheel of a bicycle, drive must be transmitted between the rear wheel axle and boss through a one-way mechanism. For this purpose, the boss is formed as an outer race of a one-way clutch, and the one-way clutch and inner race are disposed on an inner periphery of the boss.
With the increased number of speeds provided by a derailleur of a bicycle today, a multi-step sprocket wheel unit for the rear wheel includes an increased number of sprockets which is now usually at least five to seven. With the increased number of gears or sprockets, a wider range of torque can be applied from the sprockets to the freewheel. Often the sizes of the sprockets (i.e. the number of gear teeth on the sprockets) are configured for certain riding conditions, such as hilly or flat conditions. Moreover, the configuration of the sprockets or gears is designed for different rider skill levels or rider preferences. Accordingly, sometimes it is necessary to change freewheels or the entire rear wheel depending on the rider or riding conditions. Therefore, there are demands for a simplified mounting structure and an easy mounting method.
Furthermore, as the number of rear gears or sprockets have increased over the years, the freewheel has become larger and heavier. Additionally, with the increased number of gears or sprockets, rear hubs and freewheels can be complicated and expensive to manufacture and install. Moreover, with the increased number of gears or sprockets, it can be difficult to remove the rear wheel from the bicycle frame or to replace an existing freewheel with a different freewheel.
In view of the above, there exists a need for a bicycle hub with a detachable freewheel which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.